Revert of Simple cleanups related to SkFixed. (patchset #4 id:120001 of https://codereview.chromium.org/1683743005/ )

Reason for revert:
New test is failing on Windows.

Original issue's description:
> Cleanups related to SkFixed.
>
> Remove SK_FixedNaN. It does not seem to be supported or used anywhere in Skia, Chromium, Android, or Google3, (except accidentally by TwoPtRadial::kDontDrawT). I think supporting it would erase any benefit of SkFixed over float.
>
> Remove SkBitmapFilter::lookup. It does not appear to be used anywhere in Skia, Chromium, Android, or Google3.
>
> Fix a bug in SkPaint::breakText that limited it to ~5kB of text. Now it can handle more than 1GB.
>
> BUG=skia:4632
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1683743005
>
> Committed: https://skia.googlesource.com/skia/+/7ea5cb18389db11a94175de95c9db2b44972630c

TBR=mtklein@google.com,reed@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4632

Review URL: https://codereview.chromium.org/1724283003

3 files changed, 13 insertions, 2 deletions

diff --git a/src/core/SkBitmapFilter.h b/src/core/SkBitmapFilter.h
index ca3e0930f2..6fa8edde34 100644
--- a/src/core/SkBitmapFilter.h
+++ b/src/core/SkBitmapFilter.h
@@ -28,6 +28,15 @@ public:
     }
     virtual ~SkBitmapFilter() {}
 
+    SkFixed lookup(float x) const {
+        if (!fPrecomputed) {
+            precomputeTable();
+        }
+        int filter_idx = int(sk_float_abs(x * fLookupMultiplier));
+        SkASSERT(filter_idx < SKBITMAP_FILTER_TABLE_SIZE);
+        return fFilterTable[filter_idx];
+    }
+
     SkScalar lookupScalar(float x) const {
         if (!fPrecomputed) {
             precomputeTable();
@@ -58,16 +67,19 @@ protected:
     float fLookupMultiplier;
 
     mutable bool fPrecomputed;
+    mutable SkFixed fFilterTable[SKBITMAP_FILTER_TABLE_SIZE];
     mutable SkScalar fFilterTableScalar[SKBITMAP_FILTER_TABLE_SIZE];
 
 private:
     void precomputeTable() const {
         fPrecomputed = true;
+        SkFixed *ftp = fFilterTable;
         SkScalar *ftpScalar = fFilterTableScalar;
         for (int x = 0; x < SKBITMAP_FILTER_TABLE_SIZE; ++x) {
             float fx = ((float)x + .5f) * this->width() / SKBITMAP_FILTER_TABLE_SIZE;
             float filter_value = evaluate(fx);
             *ftpScalar++ = filter_value;
+            *ftp++ = SkFloatToFixed(filter_value);
         }
     }
 };
diff --git a/src/core/SkPaint.cpp b/src/core/SkPaint.cpp
index 638e251b36..d3384a628d 100644
--- a/src/core/SkPaint.cpp
+++ b/src/core/SkPaint.cpp
@@ -925,7 +925,7 @@ size_t SkPaint::breakText(const void* textD, size_t length, SkScalar maxWidth,
     GlyphCacheProc   glyphCacheProc = paint.getGlyphCacheProc(false);
     const int        xyIndex = paint.isVerticalText() ? 1 : 0;
     // use 64bits for our accumulator, to avoid overflowing 16.16
-    Sk48Dot16        max = SkScalarTo48Dot16(maxWidth);
+    Sk48Dot16        max = SkScalarToFixed(maxWidth);
     Sk48Dot16        width = 0;
 
     SkAutoKern  autokern;
diff --git a/src/effects/gradients/SkTwoPointConicalGradient.h b/src/effects/gradients/SkTwoPointConicalGradient.h
index 954b09698e..f468de8007 100644
--- a/src/effects/gradients/SkTwoPointConicalGradient.h
+++ b/src/effects/gradients/SkTwoPointConicalGradient.h
@@ -15,7 +15,6 @@
 // Should only be initialized once via init(). Immutable afterwards.
 struct TwoPtRadial {
     enum {
-        // This value is outside the range SK_FixedMin to SK_FixedMax.
         kDontDrawT  = 0x80000000
     };